U.S. 'Deeply Concerned' Over North Korea's Nuclear Weapons

Tensions are mounting between the U.S. and North Korea after a U.S. official said he is "deeply concerned" about the possible number of nuclear weapons the Asian country has.

U.S. Special Representative for North Korea Policy Sung Kim said at a recent Washington event that a recent study indicates that North Korea may have produced as many as 10 to 16 nuclear weapons in the past five years.

The study was reportedly conducted by the U.S.-Korea Institute at Johns Hopkins University's School of Advanced International Studies and assessed by the U.S. government.

Kim said at the seminar that although he cannot speak on the classified findings of the report, he remains "deeply concerned" about North Korea's secret nuclear capabilities.

"(But) obviously we are deeply concerned about the fact that the North Koreans are continuing to advance their nuclear capabilities; we know that they are continuing to work on their nuclear program," Kim said in reference to the report.

Joel Wit, a member of the research team at Johns Hopkins University, said during the research analysis presentation that North Korea is likely has 10 to 16 nuclear weapons, including some made to plutonium and some made from uranium.

"Today, Kim Jong Un is increasingly offering his own choice: between accommodation and acceptance of a nuclear-armed North Korea or periodic tensions and instability on the peninsula," Wit said. "This offer is built on the foundation of a nuclear and missile capability that is poised to rapidly expand over the next five years."